Press for amalgams and the like



July 2, 1963 N. RAY 3,095,648

PRESS FOR AMALGAMS AND THE LIKE Filed June 15, 1960 A OK M/V [HA MP4) INVENTOR.

United States Patent 3,095,648 PRESS FOR AMALGAMS AND THE LIKE Norman Landon Ray, 111 84th St., Niagara Falls, NY. Filed June 15, 1960, Ser. No. 36,239 6 Claims. (Cl. 32-40) This invention relates to a new article of manufacture in the form of a tool for applying pressure to plastic substances contained therein. 'More particularly, it relates to a tool capable of expressing uncombined mercury from an amalgam of mercury and another metal, such as silver, while said amalgam is in a plastic condition.

Silver-mercury amalgams used in dentistry for the filling of cavities in teeth are prepared by thoroughly mixing finely divided silver with mercury in such proportions that there is more mercury present than the theoretical amount required to combine or alloy with all of the silverpresent, and then removing free, uncombined or unalloyed mercury from the amalgam in various amounts and in diiferent ways, while the amalgam is still in a sufficiently plastic condition for packing into a tooth cavity.

The silver amalgam used in the last stages of packing an amalgam dentalrestoration preferably has had the maximum percentage of uncombined mercury removed from it, whereas that used in the earlier stages may retain a higher percentage of uncombined or unalloyed mercury.

The traditional method of removing mercury from a dental amalgam has been to wrap cloth or chamois leather around a portion of the silver-mercury mix and twist the cloth or chamois enclosed body of mix with one hand while holding the free portion of the cloth or chamois with the other hand. The twisting of the cloth or chamois enclosed body of amalgam causes pressure to be ing from the inadequate strength of most female dental assistants or technicians to produce an amalgam of the desired degree of dryness and the weaknes or cloth and chamois in their resistance to rupture resulting from twisting. The tendency of cloth and chamois to rupture when subjected to twisting and pressure makes it necessary for l the operator or technician to be very sensitive to the feel of the cloth or chamois covered body of amalgam when it is within a safe limit of twisting or pressure. If the technician resorts to the use of pincers or pliers to provide mechanical assistance in expressing mercury from a cloth or chamois covered body of amalgam, rupture of said cloth or chamois usually results.

Mechanical pressures heretofore proposed for the expression of excess mercury from amalgams have required too much time for the operation and have not been satisfactory.

An object of the invention is to provide a tool that will enable the user to express uncombined mercury from an amalgam, such as a silver amalgam used in dentistry, and to eject the thus expressed mercury from the vicinity of the amalgam .to prevent re-absorption thereof by the amalgam.

A further object of the present invention is to provide a press capable of expressing mercury from a plastic amalgam and permitting ready access to the chamber holding the pressed amalgam whereby to remove mercury 3,095,648 Patented July 2, 1963 from the vicinity of the pressed amalgam and to promptly obtain the pellet of amalgam from said chamber.

Another object of the invention is to provide a press that is simple and rapid in operation and which does not require excessive manual strength or dexterity to use.

Other objects of the invention are not precluded by the foregoing recital, but may be discerned from the following disclosure.

Drawings are included to ing of the invention.

In the drawings,

FIGURE 1 is a side elevation illustrating one embodiment of my invention;

FIGURE 2 is a front elevation illustrating the same embodiment of my invention as that illustrated in FIG- URE 1;

FIGURE 3 is an enlarged view, partly in section on line 3-3 of FIGURE 1, illustrating the same embodiment of my invention as that illustrated in FIGURE 1 and FIGURE 2;

FIGURE 4 is an enlarged view in section on line 4-4 of FIGURE 1, of the modification of the piston shown in FIGURES 1, 2 and 3; and

FIGURE 5 is an enlarged front elevation of another modification of the chamber of the present invention.

Referring to the drawings, three is illustrated in FIG- URES 1, 2 and 3 an embodiment of my invention comprising a pincers 11 having two lever-handles 12 and 13, two jaws 14 and 15 workable on a pivot 116, which also serves to hold the lever-handles together; each of said jaws 14 and 15, as illustrated, being bifurcated at its free end. Held between the branches of the bifurcated upper jaw 14 by means of a pivot 17, is shown a piston 18, with a free end 19, which is rotatable, within limits, about the said pivot 17. As an alternate detail of construction the jaw 14 can be made solid and without bifurcation and the piston can be made with a bifurcated upper end to fit said solid jaw, and can be pivoted thereto.

Also comprised in the embodiment of my invention illustrated in FIGURESl, 2 and 3 is a chamber QOdet-achably supported between the branches of the bifurcated lower jaw 15 by a pivot 21, which permits the chamber to rotate, within limits, about said pivot as an axis.

The piston 18 and the chamber are so alligned that when the device is held with their longitudinal axes vertical, or approximately so, and the lever-handles 12 and 13 are caused to approach each other, the free end 19 of the piston -18 will enter the open end 22 of the cham ber '20 and move within the compaction cavity of said chamber. The ease with which the free end of the piston can be caused toenter the open end 22 of the chamber 20 and the facility with which said piston and chamber become aligned by virtue of their being pivotally suspended are important features of the present invention. To accomplish and maintain satisfactory alignment-ofthe provide a clear understandpiston 18 with the compaction cavity 35 so that ready entrance of the free end 19 of the pivot 18 into the open end of the cavity can be effected, five details of design and construction must be taken care of.

First, the (longitudinal axes of the pivot 16 of thepincers '11, the pivot 17 of the piston 18 and the pivot 21 suspending the chamber 20 in the bifurcation of the lower jaw must be positioned-parallel to each other.

' Second, 'the pivots 16, Hand 21 must closely fit their respective bearings.

Third, the piston 18- and the compaction cavity 35 of the chamber "20 must be so positioned with referenceto their respective pivots that the longitudinal axes of the piston I8 and said cavity in the chamber 20 are located in one plane that is perpendicular tothe longitudinal axes or the pivots 16, 17 and 21.

the pivot 16 of the pincers and the longitudinall axis of the pivot 17 of the piston must be equal to the distance between the longitudinal axis of the pivot 16 and that of the pivot 21. If it is not desired to take full advantage of that feature of the present invention which provides for ready entrance of the free end 19 of the piston 18 into the open end 22 of the cavity 35 when the press is held with the longitudinal axes of the cavity 35 of the chamber 20 and the piston 18 vertical, the distances between the longitudinal axis of the pivot 16 and the pivot 17 of the piston 18 and between the pivot 16 and the longitudinal axis of the pivot 21 of the chamber 20 need not be equal, but, on the other hand, may be quite different.

Fifth, the joining of the lever-handles 12 and 13 by the pivot 16 must be so done that the handles will move freely and smoothly, one against the other, where they come in contact, and will be kept in close but free-moving contact by said pivot, which acts also as a rivet.

When the aforesaid five characteristics are present, the combination will function to properly align the piston 18 and the compaction cavity 35 of the chamber 20 for ready entrance of the free end 19 of said piston into said cavity. The movement of the jaws 14 and 15 will be of arcuate rotation about the pivot 16; the movements of the piston 18 and the chamber 20 will be of arcuate rotation about their respective pivots, and alignment of the piston and the cavity 35 in the chamber will be assured. Flaring the top edge 33 of the opening of the chamber serves to facilitate the entry of the free end 19 of the piston 18 into the cavity 35 of the chamber 20. The flared mouth of the chamber 20 allows the pellet of amalgam 34 to come free of the compaction cavity during ejection while still under control of a finger of the operator placed across the top of the chamber when the bottom closure stem 23 is pushed up.

Shown in FIGURES 1, 2, 3 and is a removable stem 23 protruding from the base of the chamber 20. FIGURE 3 shows the relationship of the stem 23 to the chamber 20, and also \shows the head 31, which, together with the stem 23, forms the closure means for the bottom opening 25 of the chamber 20, supported by the bottom of the cavity 35. It is desirable that the head 31 closely fit the wall of the cavity 35.

FIGURE 3, being an enlarged view, shows more clearly that the free end 19 of the piston 18 closely fits the wall of the compaction cavity 35 of the chamber 20, whereas the mid-portion of the piston does not, since it is relieved,

as FIGURE 4 allso shows, at two places 41 and 42.

It is desirable to provide sufficient space somewhere between the wall of the cavity 35 and the piston to permit the mercury expressed from the amalgam, and which is squeezed between the free end 19 of the piston 18 and said cavity wall as a film, to gather into droplets that can be shaken from the press to prevent their being reabsorbed by the amalgam. This space need not be large, but may be of the order of magnitude of a chord having a height of one sixthy-fourth ,4 of an inch in a piston having a diameter of thirteen sixthy-fourths of an inch. FIGURE 4 illustrates two such chords 41 and 42, but the invention is not limited to any particular kind of relief, except that the relieved portion or portions should be located in such area or areas of the piston as will not interfere with the smooth entrance and advancement of said piston into the cavity in the chamber. Inasmuch as the piston is permitted by its pivotal suspension to tip only rearward toward the handle end of the pincers or forward and away from the handle end of the pincers, the greatest additional aid to smooth advancement of said piston into the cavity in the chamber will be obtained from the piston itself if it closely fits the contoursof the cavity in those arcu'ate portions of said cavity that are nearest to and farthest from the handle end of the tool of the present invention. Said arcuate portions of said cavity, which are nearest to and farthest from the handle end, are hereinafter sometimes referred to, respectively, as being rearward of and forward of said compacting cavity. Similarly, the portions of the piston that are nearest to and farthest from the handle end of the tool of the present invention are hereinafter sometimes referred to, respectively, as being rearward of and forward of said piston.

By providing a close fit between the piston and the wall of the cavity 35 forward of and rearward of said piston and said chamber, the operative result is the same as though the close fit existed between the full surface of the piston and the chamber wall because the lever-handles of the pincers, being held together in close contact by the pivot 16, permit only rotative movement of the jaws 14 and 15 about said pivot. Hence, the piston can move only slidably along those portions of its surface which are in close contact with said cavity wall.

FIGURE 5 illustrates a modification of the chamber forming a part of my invention, in which parts of the wall 51 of the chamber 52 are extended to provide lugs 53 and 54 suitable for receiving the pivots 55 for suspending the chamber 52 in close fitting hearings on the lower jaw 15 and between the branches 15a and 15b thereof. As in the case of the chamber shown in FIGURE 3, the chamber 52 illustrated in FIGURE 5 has a bevel at its open end to facilitate entry of the free end 19 of the piston into the open end 22 of the chamber, and has its pivots 55 oriented and spaced in the same manner as in the case of the said chamber 20.

The location of the pivots 21 and 55 by which the chamber 20 or 52 is suspended from the lower jaw 15 of the pincers 11 is of especial importance in the present invention, because it is desirable to have the longitudinal axes of the piston and the compacting cavity in the chamber coincide, particularly when the tool is being used to squeeze material in the compacting cavity of the chamber, because such coincidence will permit the piston 18 to move into the compacting cavity 35 of the chamber 20 without any tendency toward binding between the piston and the wall of the cavity in the chamber. On the other hand, if the longitudinal axis of the piston does not coincide with the longitudinal axis of the compacting cavity 35 when the free end 19 of the piston 18 begins to exert pressure on the material in said compacting cavity and while said material is being subjected to pressure by the free end of the piston, there will be a tendency for the piston to bind in the cavity. The magnitude of that tendency to bind will depend upon the degree of noncoincidence or divergence of said axes; the greater the degree of non-coincidence or divergence, the greater will be the tendency of the piston to bind as it is forced into the cavity.

Maintenance of the condition of freedom from binding because of the coincidence of the longitudinal axes of the piston 18 and the compacting cavity 35 of the chamber 20 is the more easily obtained the greater the distance, within reason, between the longitudinal axis of the pivots 21 or 55 of the chamber and the level at which the material in the compacting cavity of the chamber 20 is first engaged by the free end 19 of the piston 18 in a squeezing action.

If the charge of material in said cavity were non-uniformly distributed and the upper level of said charge were to be higher in the cavity than the longitudinal axis 21 or 55 of the pivot of the chamber, the pressure of the piston 18 against the charge would be unevenly distributed over the top surface of the charge with the consequence occur under the foregoing conditions.

lever-handles 12 and 13 toward each other.

amalgam to be expressed therefrom.

On the other hand, when the construction of the chamber 20 and its suspension are such that the free end 19 of the piston 18 cannot engage the uppermost surface of the charge and apply pressure thereto until after the said free end has penetrated into the compacting cavity beyond the longitudinal axis of the pivot 21 or 55 of the chamber, the tendency toward binding between the piston and the cavity is substantially reduced, and the further the free end of the piston has passed beyond the longitudinal axis of the pivot 21 or 55 of the chamber 20 before it engages the uppermost surface of the charge, the smaller will be the tendency of the piston to bind in the compasting cavity of the chamber.

Hence, the chamber 20 and its pivotal suspension should be so designed that the volume of said compacting cavity 35 will be equal to and preferably will exceed, the intended maximum volume of charge to be placed in said compacting cavity and that the free end of the piston will pass the longitudinal axis of the pivot 21 or 55 of the chamber and enter the compacting cavity before it engages the top of said maximum volume of charge in the cavity 35.

The said compacting cavity will have a wall that closely fits the free end 19 of the piston 18 and may have a depth extending from the longitudinal axis of the pivot 21 of the chamber 20 to the bottom of the cavity as required to provide a receptacle of sufficient volume to receive the maximum intended charge of material. It is preferable, however, to limit the height of the compacting cavity above the bottom or base thereof to a distance short of the longitudinal axis of the pivot 21 of the chamber 20 by an amount equal to or greater than the radius of the pivot 21 or 55.

The kind of material or materials from which are various parts of the present invention are to be made have not been specified because it is considered to be within the province of a tool-maker to choose materials suitable for the purpose. Mechanical strength and corrosion resistance are mentioned here as factors to be considered in choosing the material or materials to be used in the manufacture of the tool of the present invention, and naturally resistance to amalgamation is of great importance.

To use the device described herein, the chamber 20 or 52, with the stem 23 and its head 31 in place, is removed from the lower jaw 15. The material, such as an amalgam of silver and mercury, used in dentistry, which is to be compacted or squeezed is then placed in the compaction cavity 35 oi the chamber 20, and the chamber is hung on the bifurcated lower jaw 15 by the pivots 21 or 55, as the case may be.

After the free end 19 of the piston 18 has been entered into the open end 22 of the chamber 20 and before pressure has been applied to the charge in the cavity 35 by squeezing the handles together, the tool is turned so that the piston is downward and the chamber is upward. While in that orientation, the piston and chamber end of the tool is held over a suitable receptacle while pressure is applied to the charge in the compaction cavity by squeezing the Squeezing the handles toward each other with sufiicient pressure will cause free or uncombined mercury contained in the Such expressed mercury will pass between the cavity wall and the closely fitting end of the piston as a thin filmthat will gather into droplets in those larger spaces where the piston has been relieved and does not closely fit the compaction cavity wall. Such droplets will drop into the receptacle mentioned above when the tool is oriented as described above. Those droplets that cling to the chamber of the tool are then removed therefirom by sharply shaking the tool with the piston and chamber end over said receptacle and with the piston downward.

A pincers having approximately a five to one ratio (5:1) of'the length of the pressure arms to the length of the jaws, provides a suitable mechanical advantage to enable a female dental technician to readily express from a plastic silver-mercury amalgam sufiicient uncombined or unalloyed mercury to leave an amalgam of any degree of dryness desired by the dentist, even one containing a minimum percentage of uncombined mercury.

When the amalgam has had the desired amount of uncombined or unalloyed mercury expressed therefrom, the chamber 20 or 52 is removed from its supporting jaw 15 and the stem 23, which forms a part of the bottom closure means, is struck against a rigid body, whereupon the head 31 of the bottom closure means lifts the pellet of amalgam from the compaction cavity to the top of the chamber, where it can be lifted oif the closure means head and is ready for use.

Although the disclosure and drawings describe the present invention in detail, it is to be understood that the invention is capable of variation and modification without departure from the substance of the invention or the sp'n'it of the appended claims.

Having thus described and illustrated my invention, I claim:

1. As a new article of manufacture, a press comprising a pair of jaws supported in movable relationship, a piston pivotally supported by one of said jaws, the other of said jaws being bifurcated, and having a chamber pivotally supported between the branches of said bifurcation, said chamber having a compaction cavity therein located below the longitudinal axis of the pivotal support of said chamber and; being open at its pivoted end and positioned to receive the free end of said piston in said open end, and means for moving said piston into said compacting cavity.

2.. As a new article of manufacture, a press comprising a pair of bifurcated jaws supported in movable relationship, a piston pivotally supported at one end thereof by one of said jaws, a chamber pivotally supported by the other of said jaws, said chamber having a compaction cavity therein located below the longitudinal axis of the pivotal support of said chamber and being open at its pivoted end and positioned to receive the free end of said piston in said open end, and means for moving said piston into said compacting cavity.

3. As a new article of manufacture, a press comprising a pincers having a pair of bifurcated jaws, a piston pivotally held at one end thereof by one of said jaws, a chamber pivotally supported by the other of said jaws, said chamber having a compaction cavity therein located below the longitudinal axis of the pivotal support of said chamber and being open at its pivoted end and positioned to receive the free end of said piston in said open end of said chamber.

4. As a new article of manufacture, the press defined in claim 3 characterized by having a movable stem protruding from its base and communicating with a bottom closure head within its compaction cavity.

5. As a new article of manufacture, the press defined in claim 4 characterized by having the longitudinal axes of the pivots of the pincers, the piston and the chamber parallel to one another, and the longitudinal axes of the pivots of the piston and the chamber located at the same distance from the longitudinal axis of the pivot of the pincers.

6. As a new article of manufacture, the press defined in claim 5 characterized by having the longitudinal axes of the piston and the compaction cavity located in a plane that is perpendicular to the longitudinal axes of the pivots of the pincers, the piston and the chamber.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AS A NEW ARTICLE OF MANUFACTURE, A PRESS COMPRISING A PAIR OF JAWS SUPPORTED IN MOVABLE RELATIONSHIP, A PISTON PIVOTALLY SUPPORTED BY ONE OF SAID JAWS, THE OTHER OF SAID JAWS BEING BIFURCATED, AND HAVING A CHAMBER PIVOTALLY SUPPORTED BETWEEN THE BRANCHES OF SAID BIFURCATION, SAID CHAMBER HAVING A COMPACTION CAVITY THEREIN LOCATED BELOW THE LONGITUDINAL AXIS OF THE PIVOTAL SUPPORT OF SAID CHAMBER AND; BEING OPEN AT ITS PIVOTED END AND POSITIONED TO RECEIVE THE FREE END OF SAID PISTON IN SAID OPEN END, AND MEANS FOR MOVING SAID PISTON INTO SAID COMPACTING CAVITY. 